Open-circuit to embedded pattern approach with harmonic optimization in ESPAR

The radiation characteristics of Electronically Steerable Parasitic Array Radiators (ESPAR) can be modified by changing the loads attached to the parasitic radiators. The open-circuit pattern to embedded pattern approach is employed to compute the radiation pattern, when dynamic loads are attached to the parasitic radiators. It provides results exactly matching to those of full-wave simulations without any approximation and it is computationally highly efficient in the optimization phase. The weighted mean squared error is used as a cost function for optimization to obtain the objective radiation pattern. The optimization is carried out using a harmonic decomposition of load values versus the position index of parasitic elements and it provides results within a minute with an average error below 1dB between objective radiation pattern and obtained radiation pattern within the main lobe.